Butyrolactone is a known compound which is employed in the synthesis of pyrrolidone, glutaric acid, and many other compounds. Improved processes for preparing butyrolactone are of interest to the chemical industry.
The following references disclose known processes for making butyrolactone. U.S. Pat. No. 4,096,156 discloses a process for the preparation of gamma-butyrolactone by catalytic hydrogenation of maleic acid, maleic acid anhydride, succinic acid, succinic acid anhydride, or fumaric acid, or of a mixture of two or more of these compounds. The catalyst contains a mixture of an element of the VIII.sup.th subgroup of the periodic system of elements or of one of its compounds with an element of group IB of the periodic system of elements or of one of its compounds.
U.S. Pat. No. 4,105,674 discloses a process for producing gamma-butyrolactone by hydrogenating a feed compound selected from the group consisting of maleic acid, succinic acid, maleic anhydride, succinic anhydride, and mixtures of any of the foregoing in the vapor phase. The reaction is conducted in the presence of a Cu-Pd or Cu-Pt catalyst.